• 한국자동차공학회논문집
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• 제21권1호
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• pp.121-127
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• 2013

In this study, suspension geometry is controlled to improve vehicle handling performance. The toe and camber of the rear suspension is controlled independently by using a double knuckle structure designed to enhance the vehicle cornering stability. Camber and toe changes in the rear wheel during high speed turning maneuver are important factors that influence the vehicle stability. Toe in the rear outer wheel plays a dominant role in cornering. A control algorithm for the camber and the toe angle input is developed to carry out the control simulation of the vehicle such as single lane change, the steady state cornering, the double lane change and the step steering simulation. Effects of the camber and toe angle control are analyzed from the computer simulations. A double lane change simulation revealed that the suspension mechanism with variable camber angle and variable toe angle decreases the peak body slip angle and peak yaw rate, 50% and 10%, respectively.

• 공학교육연구
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• 제13권2호
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• pp.38-42
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• 2010

It is necessary for lower grade students to study the correct usage of tools as a base of the technical education for dismantling and assembling various machines. However, enough understanding has not been obtained though the usage of these tools when training first grade students. So, we started to develop a teaching text and materials within the students' practice curriculum based on the dismantling and assembly of all-terrain vehicle [ATV]'s, which is a very motivating for lower grade students. This practice makes the student learn both how to use the tools and the steering mechanism of cars through the dismantling and assembling of the ATV. It is possible to not only have the student learn about the knowledge obtained through the practice, but also they also acquire wider and deeper knowledge through making the text and teaching materials for the practice. The textbook and secondary educational materials of this practice curriculum were created in cooperation with a fifth grade student as part of their graduation research. As a result, an effective teaching and learning text and secondary educational material regarding manufacturing practice could be developed from the student's point of view. Making a teaching text and materials is effective for promoting the study and experience of engineering.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.435-442
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• 2004

Tilting train allow the train to pass curve at higher speed without affecting passenger comfort. As the tilting trains run curve track about 30$\%$ higher than non-tilting trains, the centrifugal force and dynamic force will be higher. Therefore it is very important for tilting train to ensure safety against derailment, and to reduce the lateral track forces by applying light-weight design, optimized suspension design and steering mechanism. The 180 km/h Korean Tilting Train(TTX) which is now developing as a part of the Korean National R & D project, was designed and analytically verified to meet these special requirements. This paper describes the analytic study to verify the safety against derailment, especially on the wheel unloading in case of tilting actuation. The severest curve geometry and curving speed was assumed, the tilting control pattern was also assumed as trapezoidal force function applied to tilting bolster and bogie frame. For the comparison, the operation with the speed of tilting train without tilting actuation was numerically simulated and the operation with the balanced speed without tilting actuation was also numerically simulated. Through the numerical simulation of various operating case, we found that derailment quotients, wheel unloading and Q/P was not affected by tilting actuation and that the bogie of TTX was nicely designed to satisfy the safety against the derailment.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권4호
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• pp.201-212
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• 2000

In this paper, an adaptive mechanism based on immune algorithm is designed and it is applied for the autonomous guided vehicle(AGV) driving. When the immune algorithm is applied to the PID controller, there exists the cast that the plant is damaged due to the abrupt change of PID parameters since the parameters are adjusted almost randomly. To solve this problem, a neural network is used to model the plant and the parameter tuning of the model is performed by the immune algorithm. After the PID parameters are determined in this off-line manner, these gains are then applied to the plant for the on-line control using immune adaptive algorithm. Moreover, even though the neural network model may not be accurate enough intially, the weighting parameters are adjusted to be accurate through the on-line fine tuning. The computer simulation for the control of steering and speed of AGV is performed. The results show that the proposed controller has better performances than other conventional controllers.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.228-235
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• 2016

Flaws at dissimilar metal welds (DMWs), such as reactor coolant systems components, Control Rod Drive Mechanism (CRDM), Bottom Mounted Instrumentation (BMI) etc., in nuclear power plants have been found. Notably, primary water stress corrosion cracking (PWSCC) in the DMWs could cause significant reliability problems at nuclear power plants. Therefore, phased array ultrasound is widely used for inspecting surface break cracks and stress corrosion cracks in DMWs. However, inspection of DMWs using phased array ultrasound has a relatively low probability of detection of cracks, because the crystalline structure of welds causes distortion and splitting of the ultrasonic beams which propagates anisotropic medium. Therefore, advanced evaluation techniques of phased array ultrasound are needed for improvement in the probability of detection of flaws in DMWs. Thus, in this study, an investigation of focusing and steering phased array ultrasound in DMWs was carried out using a time reversal technique, and an adaptive focusing technique based on finite element method (FEM) simulation. Also, evaluation of focusing performance of three different focusing techniques was performed by comparing amplitude of phased array ultrasonic signals scattered from the targeted flaw with three different time delays.

• 한국항만학회지
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• 제14권2호
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• pp.187-197
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• 2000

In this paper, an adaptive mechanism based on immune algorithm is designed and it is applied to the driving control of the autonomous guided vehicle(AGV). When the immune algorithm is applied to the PID controller, there exists the case that the plant is damaged by the abrupt change of PID parameters since the parameters are adjusted almost randomly. To solve this problem, a neural network used to model the plant and the parameter tuning of the model is performed by the immune algorithm. After the PID parameters are determined through this off-line manner, these parameters are then applied to the plant for the on-line control using immune adaptive algorithm. Moreover, even though the neural network model may not be accurate enough initially, the weighting parameters are adjusted more accurately through the on-line fine tuning. The experiment for the control of steering and speed of AGV is performed. The results show that the proposed controller provides better performances than other conventional controllers.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.295-300
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• 2001

In recent years, as changing the habit of eating, the pathology in the colon grows up annually. For that reason, the colonoscopy is generalized. But it requires much time to acquire a dexterous skill to perform an operation. And the procedure is painful to the patient. Therefore, biomedical and robotic researchers are developing a locomotive colonoscope that can travel safely in colon. In this paper, we propose a novel design and concept of semi-autonomous colonoscope and two actuators for the micro robot. The micro robot comprises camera and LED for diagnosis, steering system to pass through the loop, pneumatic actuator and bow-shaped flexible supporters to control a contact force and to keep the space between colon wall and the actuator. For actuating mechanism, we suggest two models. One is based on the reaction force, and the other is impact force. In order to validate the concept and the performance of the actuators, we carried out the preliminary experiments in rigid pipes.

• 경영과정보연구
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• 제36권2호
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• pp.277-306
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• 2017

그동안의 기업 정보화 성공요인 관련 연구들은 정보화 자체의 구축 완성도 및 그 재무적 효과에 초점을 맞추고 있어, 정보화의 방향성이 경영전략을 지원할 수 있는지에 대한 연구가 미흡하였다. 기업의 정보화가 경영전략 이행을 주도할 수 있도록 초점이 맞추어져 있는지, 주요 메커니즘 요인이 정보화 성과에 어떠한 연관성을 갖는지에 대한 검증이 필요하며, 이는 기존의 정보화 성공요인들을 경영 전략적 패러다임으로 재해석하는 연구가 필요하다는 것을 시사한다. 본 연구는 국내 기업을 대상으로 주체, 환경, 자원 및 메커니즘 요인이 정보화 성과에 어떠한 영향력을 갖는지를 검증하고, 국내 대기업과 중소기업에 있어 정보화 성공요인이 정보화 성과에 미치는 영향도의 차이가 있는지에 대한 문제를 실증적으로 분석하였다. 본 연구를 통해 7개의 연구가설에 대한 검증 결과를 제시하였다. 기업에 있어 자원 요인의 확보는 정보화 성과에 유의미성이 있다는 것과 메커니즘 관점에서 학습 메커니즘과 조정 메커니즘의 모든 하부 요인들은 기업의 정보화 성과에 유의미하다는 것을 실증 분석을 통해 확인하였다. 또한, 기업 규모에 따른 통제효과분석을 통해 대기업과 중소기업의 정보화 성과에 대한 차이점을 지원 환경 요인, 선택 메커니즘 요인 및 학습 메커니즘 요인 등에 있음을 밝혔다. 본 연구의 시사점은 첫째, 메커니즘 요인 변수의(학습, 내부 조정, 외부 조정) 정보화 성과에 대한 유의미성이 다른 요인 변수에 비해 상대적으로 중요하게 활용되고 있음을 확인하였다. 둘째, 대기업과 중소기업의 정보화 성과에 대한 차이점을 밝혀 중소기업이 중점적으로 확보해야 하는 정보화 성과 요인을 제시 하였고, 셋째, 본 연구는 선행 연구에서 다루지 못한 정보화 성과 창출 메커니즘 요인에 대한 실증연구를 진행했으며, 이는 메커니즘 요인에 대한 보다 더 깊이 있는 이해를 가능하게 하였다. 또한, 본 연구의 사례를 기반으로 타 산업 영역과 기업군에도 적용할 수 있다.

• 한국정보통신학회논문지
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• 제15권6호
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• pp.1238-1244
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• 2011

본 논문은 레이저 내비게이션의 위치측정을 위한 반사체 매칭방법을 제안하다. 레이저 내비게이션은 벽면에 부착된 반사체의 각도와 거리를 측정하는 장치이고 위치를 측정하기 위해서는 반사체의 매칭 기법이 필요하다. 대표적인 매칭 방법으로는 측정된 반사체의 위치를 이미 알고 있는 반사체의 위치로 평행 이동 한 후, 회전 하면서 매칭하는 방법이었다. 하지만 이 방법은 연산량이 많고 외란에 약하다는 단점이 있다. 이에, 본 논문에서는 연산량을 줄이고 외란에 강인한 반사체 매칭 방법을 제안한다. 제안된 방법은 계측된 반사체들의 위치를 설치된 반사체의 실제 위치로 생성한 후, 계측된 반사체들을 회전하면서 매칭하는 방법이다. 실험은 직접 설계한 AGV를 이용하였으며 조향각과 주행속도를 변화 시키면서 위치측정 정밀도를 비교하였다.

• 디지털융복합연구
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• 제16권4호
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• pp.39-47
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• 2018

본 연구는 우리나라 제4차 산업혁명 대응에 있어 사회-기술시스템론적 공공관리의 적용 가능성을 살펴보는데 목적이 있다. 이를 위해 제4차 산업혁명의 주요 개념과 논의점 검토와 함께 해외 선도국가들의 대응 전략을 국내외 문헌 연구를 통해 분석하였다. 이를 통해 본 연구는 기술 중심에서 벗어나 사회적 난제 해결과 인간중심의 사회 혁신을 위해 제4차 산업혁명을 이끄는 정부 정책기조의 변화 필요성을 강조하였다. 즉 제4차 산업혁명의 변화에 대응하여 사회적 난제를 해결하기 위해서는 기존의 수직적, 계층적, 분화적, 기계적 정부시스템을 과감히 탈피하고, 사회-기술시스템론적 공공관리 방식을 강조해야 한다고 보았다. 향후 정부의 정책 방향은 혁신을 확산할 수 있는 창발적이며 내재적인 모습을 보여야 하며, 정부조직과 정부운영방식의 재설계, 정부 정책영역의 재설정과 이를 입법적으로 뒷받침하는 입법행정의 공조 전략이 필요하다. 본 연구는 공공부문의 제4차 산업혁명 대응성 강화를 위한 정책연구의 첫 논의라는 점에 의미가 있으며 후속연구가 이러지기를 바란다.